I'm not sure what you consider to be the source(s) of "emotional abuse" for a Help Desk or call center employee, but nobody who works on the phones for customer

I'm not sure what you consider to be the source(s) of "emotional abuse" for a Help Desk or call center employee, but nobody who works on the phones for customers is required to endure any sort of egregious verbal abuse from them. Such a worker should be free to warn them, and then hang up or refer the to management as appropriate. It is certainly a good skill to be able to defuse situations where the customer is angry and ranting, but there is hopefully no personal or intimate connection with said customers, and that's really the key to effective emotional abuse. Likewise, the worker is hopefully not enduring emotional abuse from coworkers or management in the course of their jobs, although this is also a possible thing.